The amendment, which says “the right of farmers and ranchers to engage in farming and ranching practices shall be forever guaranteed,” passed with 50.13 percent of the vote.

Nearly 1 million votes were cast after a hot public debate. The amendment was approved by only 2,528 votes (a 0.25% margin), according to the initial, unofficial tally.

The narrow margin opens the possibility of a recount after the results are certified. Certification could take about three weeks, Secretary of State Jason Kander has said.

Missouri State Rep. Bill Reiboldt (R) originally sponsored the right-to-farm amendment to keep animal rights activists from threatening the operation and financial integrity of farms and ranches. Animal rights advocates are currently pushing for larger, more roomier pens for chickens and hogs, which livestock growers say will require extensive retro-fitting and remodeling.

But opponents of the law fear it will allow factory farms to proliferate regardless of adverse affects to the environment, the welfare of livestock and smaller scale operations.

Missouri would be only the second state to adopt a right to farm amendment, joining North Dakota.

The Missouri amendment says:

“That agriculture which provides food, energy, health benefits, and security is the foundation and stabilizing force of Missouri's economy. To protect this vital sector of Missouri's economy, the right of farmers and ranchers to engage in farming and ranching practices shall be forever guaranteed in this state, subject to duly authorized powers, if any, conferred by article VI of the Constitution of Missouri.”

Article VI refers to the structure of the state’s cities and counties.